What is an AVM?

8 min read  |  November 01, 2021  | 

It’s no secret that the human body is an incredible machine with a complex network of organs and arteries that function perfectly together. Sometimes, however, that network malfunctions in ways doctors still struggle to understand.

Joseph Zikria, M.D., a board-certified diagnostic and interventional radiologist, is working to advance the understanding, diagnosis, and treatment of malformations of the blood vessels. Sometimes called arteriovenous malformations (AVMs), this complex condition occurs when arteries, veins, and capillaries don’t develop normally, and it affects blood flow.

This usually happens when a baby is still in its mother’s womb. However, it can also show up after an injury or when the body undergoes a significant hormonal change such as puberty or pregnancy.

Vascular malformations are rare; typically, they affect less than 1% of the population, but those are just the people who have been diagnosed. “These rare anomalies are often misdiagnosed, but the more they are discussed, the more I hear from people who say, ‘I’ve had this all my life,’ or, ‘I now understand why my grandfather died of a brain bleed,’” says Dr. Zikria, who studied vascular malformations at Yale University School of Medicine and Lenox Hill Hospital in New York City

He suspects that vascular malformations are more common than previously thought.

Over the past few decades, the condition has gained more awareness in medical circles. In the 1980s, an AVM “grading system” was developed that helped doctors estimate the risks of surgical treatment for AVM. This evaluation method is based on the AVM size, location, surrounding tissues, and potential leakage. And as imaging technology has progressed, it has improved understanding of brain AVM.

AVMs across the spectrum

AVMs made the news in 2021 when Casey Martin, a former PGA Tour golfer and current Oregon golf coach, had his right leg amputated. Martin has had Klippel-Trenaunay-Weber Syndrome (KTS) since birth, a condition that restricts blood flow to his lower right leg. Some people with KTS also have malformed veins that affect their bones, joints, muscles, skin, and underlying fat. This puts them at risk for infection and blood clots.

Parkes-Weber Syndrome is like KTS. It shows up as a high-flow or high-pressure AVM in the arm or leg. “There’s a spectrum to these anomalies. Some are high-flow; others are low- flow,” Dr. Zikria says. High- or low-flow refers to the amount of blood flowing to a limb because of an abnormally-formed artery, vein, or capillary system.

CLOVES encompasses several conditions. It affects babies and children and typically shows up as excess fatty tissue in the head, neck, feet, limbs, and torso. It can lead to tumors, and some children develop a reddish-purple skin rash often mistaken for a port-wine birthmark. CLOVES can also cause spinal deformities such as scoliosis and other malformations. Lauren Yarholar, M.D., a plastic surgeon with UHealth, works with Dr. Zikria to treat pediatric and adult patients. “Swelling and bruising in newborns is often attributed to trauma from the birthing process, but can indicate an AVM,” Dr. Yarholar says.

Bean Syndrome causes venous malformations on the skin, underlying tissue, intestines, and other internal organs.

Hereditary Hemorrhagic Telangiectasias (HHT), also known as Osler-Weber-Rendu, is passed down from parents to children. It can cause malformations in the smaller arteries or blood vessels of the nose, skin, hands, feet, lungs, and liver.

UHealth experts team up to treat AVMs.

Vascular malformations appearing in the brain or spine are the most common form of this condition and are known as neurological or brain arteriovenous malformations. However, malformations can appear just about anywhere in the body, which is why Dr. Zikria, along with the Chair of the Department of Interventional Radiology, Shivank Bhatia, M.D., formed a multidisciplinary team to study, diagnose, and treat the condition. Their team includes neurologists, cardiologists, pulmonologists, gastroenterologists, plastic surgeons, dermatologists, and genetic testing specialists. The team meets to review and discuss patient cases, and treats all types of malformations, with a special emphasis on HHT.

Dr. Bhatia and Dean Henri Ford of the University of Miami Miller School of Medicine want to create an international presence for treating HHT, as well as doing research and training physicians in the medical management of this condition, Dr. Zikria says. “We’re working with Cure HHT, an international organization, to develop an HHT center. Part of our advantage at UM is having so many experts from different disciplines working together to diagnose and treat this anomaly. The next closest HHT center is in Georgia, so there’s a great need for one in Florida.”

According to Cure HHT, about one in 5,000 people have the disorder, but 90% of people are still undiagnosed.

People can live their whole lives without realizing they have an arteriovenous malformation.

Others, like Casey Martin, are less fortunate. Depending on where the malformation is found, symptoms can range from annoying to life-threatening:

  • Nosebleeds
  • Red or purplish spots on the skin that lighten when touched, sometimes mistaken for a port-wine birthmark
  • Painful bump or swelling in the skin
  • Headaches
  • Backache
  • Muscle weakness
  • Facial paralysis
  • Drooping eyelids
  • A buzzing or rushing sound in the ears
  • Vision changes
  • Trouble speaking
  • Dizziness or balance issues
  • Cold or blue fingers
  • Changes in ability to smell
  • Blood in stool
  • Seizures
  • Loss of consciousness
  • Bleeding
  • Ulcers
  • Coughing blood
  • Stroke

When the arteries and veins inside a malformation rupture, they can cause bleeding in the brain or into other parts of the body, such as the spinal cord. That’s why early diagnosis is so important.

How is the malformation diagnosed?

If you have any of the previously mentioned symptoms and/or a family history of AVM, brain bleeds, or symptoms associated with malformations, see your doctor and ask for a CT scan or magnetic resonance imaging (MRI). Those are the diagnostic imaging tests Dr. Zikria prefers, but he also uses ultrasound and fluoroscopy. The latter method uses dye to “map out” a malformation. If you have a strong family history of this condition and experience symptoms associated with this condition, Dr. Zikria urges you to visit a specialized vascular facility where doctors “won’t miss a rare anomaly.”

Can an AVM be treated?

Doctors cannot prevent or cure arteriovenous malformations. Once you are diagnosed, there are several treatment options:

  • Watchful waiting with your doctor and regular follow up visits
  • Medication
  • Laser therapy
  • Embolization, a procedure that closes off a blood vessel
  • Sclerotherapy, which injects a chemical that closes off a vessel
  • Surgical removal and reconstruction if needed
  • Since malformations can recur, multiple treatments may be needed.

Since malformations can recur, multiple treatments may be needed. Dr. Yarholar’s expertise is especially helpful when an AVM occurs in the facial area. AVMs around the eyebrow, for example, can grow large enough to block the vision. “Dr. Zikria can shrink or ‘scar off’ the blood vessel with sclerotherapy, or clot off the vessel through embolization. This stops blood loss and makes it easier for me to see the area. I can then ‘de-bulk’ the engorged vessel, manipulate the soft tissue, and flatten the brow area to improve vision,” Dr. Yarholar says. In some cases, plastic surgery isn’t necessary. She recalls a patient whose lip was enlarged from an AVM. She referred to patient to Dr. Zikria, who corrected the problem without the need for additional surgery.

Aesthetics aside, Dr. Yarholar also uses plastic surgery to reduce nerve pain from an AVM by “resectioning or dissecting off the nerves.” While she maintains that “interventional radiologists like Dr. Zikria are the true heroes” of AVM care, plastic surgeons and other providers on the multidisciplinary team allow interventional radiologists to fine-tune their treatments.

Potential complications

Left untreated, these abnormal vessels can cause other health problems:

  • Stroke
  • Numbness
  • Problems speaking or moving
  • Developmental delays in children
  • Hydrocephalus (a buildup of spinal fluid in the brain)
  • Hemorrhage (uncontrolled bleeding)
  • Loss of a limb

When should I see a doctor?

Vascular anomalies can stay hidden until a rupture or bleed happens. Again, the previously mentioned symptoms call for medical attention. If the symptoms are severe, you should seek emergency care or call 911.

Dr. Zikria says that family history plays a major role in many malformations, especially HHT. “HHT is rare but has a very strong genetic component in some families. We’re treating multiple generations of families. It’s important to identify this condition so we can treat future generations.”

To schedule an appointment with Dr. Zikria, call 305-243-1815. To schedule an appointment with Dr. Yarholar, call 305-243-7500.

Nancy Moreland is a regular contributor to UMiami Health News. She has written for several major health care systems and the CDC. Her writing also appears in the Chicago Tribune and U.S. News & World Report.

Tags: artery malformation, AVMs, blood flow, capillary malformation, Dr. Joseph Zikria, Dr. Shivank Bhatia, genetics, vascular disease

Continue Reading